Hot-air furnace.



Patented; June [2, L900.

J. J. KNAPPENBERGEB.

No. 65l,763.

HOT AIR FURNACE.

(Application filed Ail 2a, 1899.)

(No Model.)

JNVENTOR r 7 J55);

WITNESSES Attorney UNITED STAT S PA ENT OFFICE.

JOHN J. KNAPPENBERGER, OF GREENSBURG, PENNSYLVANIA.

HOT-AI R FU RNACE.

SPECIFICATION forming part of Letters Patent No. 651,763, dated June 12,1900.

Applioationfiled August 26, 1899.' Serial No- 728,5 33. (No model.)

heat and to utilize the heat arising from the 7 products of combustionwhich ordinarily escapes through the smoke-fines of a furnace.

Further objects of the invention are to effectually prevent the escapeof gases from the combustion-chamber of the furnace into the hot-airchamber thereof and to provide an improved construction which willinsure a regular flow of heat to the hot-air flues.

The construction of the improvement and its novel features will be fullydescribed hereinafter and defined in the appended claims in connectionwith the accompanying drawings, which form a part of this specification,and in which Figure 1 is a front elevation of a furnace embodying myinvention. Fig. 2 is a central vertical section thereof. Fig. 3 is ahorizontal sectional view on a plane extending through the fuel-openingof the furnace, with the box or casing fitting said opening removed.Fig. 4 is a detail perspective view illustrating the manner of securingthe door of the fuel-opening in position. Fig. 5 is 'adetail sectionalview showing the means for connecting the dome of the combustion-chamberto the inner wall thereof. v

The reference-numeral 1 designates the outer wall or casing of thefurnace, which is preferably circular in cross-section and built offire-brick and of rounded or dome shape at its upper end. Within theouter wall 1 is an inner casing 2 of fire-brick, constituting thecombustion-chamber and built concentric with the outer wall 1 and at asufiicient distance therefrom'to leave an annular hot-air space 3between them. The upper end of the inner wall 2 converges to cause theheat to strike its inner surface, and said upper end terminates belowthe dome or roof of the outer wall and is closed by a cast-metal dome 4,formed with an annular horizontal flange 5,

which rests upon the top of the wall 2; Sur

rounding the combustion -chamber 2 is a jacket 6 of sheet metal, whichextends above the top of the chamber 2, the annular space between thejacket and outer surface of the dome 4 being filled with fire-claymortar, as shown at 7, which secures the dome in place and effectuallyprevents the escape of gases from the combustion-chamber into the hotairchamber 3. The walls 1 and 2 and jacket 6 rest upon a suitablefoundation, and the lower end of the jacket 6 is embedded in a layer 9of cement.

The walls and jacket are formed with alined openings to receive ametallic box or casing 10, through which fuel is introduced into thecombustion-chamber. To secure this casing, the jacket 6 is formed withflanges 11, struck up from the jacket and bolted to the casing,as'clearly shown in Fig. 4. The inner end of the casing 10 extendsbeyond the jacket 6 to form a flange 12 to receive the inner wall 2. Adoor 13, having the usual damper 14, is hinged to the front end of thecasing. Below the casing 10 the jacket 6 and inner wall 2 are formedwith an opening 15, serving as a stoke-hole.

16 designates the grate, and 17 the ash-pit, of the furnace, a hingeddoor 18 being employed to close the stoke-hole and ash-pit.

19 designates the smoke-pipe of the furnace, extending from the side ofthe dome'i through the outer wall 1, as shown.

Any desired number of hot-air pipes extend through the outer wall 1 toconduct the hot airto the various floors or apartments of the building.

built of fire-brick laid in fire-clay mortar.

I claim- 1. In a hot-air furnace, the combination with an outer wall, ofan inner wall constituting a combustion-chamber, and so arranged withinthe outer wallas to form an annular hot-air space; azmetallic domehawizugla'flan ge Y seated on the "inner wall; a metallic jacket.surrounding the innerwall and projecting above the latter to form anannular space be-j tween the jacket and dome; and a. filling of plasticmaterial for said space.

2. In a-hot-air furnace, the combination with the outer wall ofmasonry-work closed: and rounded at its upper end; of an inner" wallconstituting a combustion-chamber andarranged within the outer wallconcentric therewith to form an annular hot-air cham-' ber; a flangedmetallic dome closing the upbustion-chamber, and a door for said-casing.

In testimony whereof I aflix my signature .in presence of two witnesses.

JOHN J. KNAPPENBERGER.

Witnesses:

H. W. WALKINsHAw,

ARMBRUST.

